This invention relates to an improvement in an adjustable boring bar assembly and particularly to a lateral bar assembly improvement of the invention disclosed and claimed in U.S. Pat. No. 2,838,316 issued to Albert Thomas, a co-inventor of the present invention, and assigned to Joseph M. Roman, the other co-inventor of this invention.
The lateral bar improvement of this invention permits the use of a multi-diameter single boring bar assembly, such as are used with on lathes, milling machines, or boring mills. As is well known boring bar assemblies are limited in the range of diameters over which they may operate. In a typical operation using a single boring bar assembly, the small diameters of operation are achieved by a cutting tool mounted axially in a bit holder. To get larger diameter operation with that same boring bar assembly the bit holder is replaced with another holder adapted to support a bit which extends generally radially of the bit holder. The range of diameters acheived in that manner is limited to a small range. Should larger diameters be needed an altogether different and larger boring bar assembly would be required. Thus, a wide range of diameters may only be achieved by having multiple boring bar assemblies. Boring bar assemblies, as is well known, are very expensive and having to stock a number of different sized boring bar assemblies is financially burdensome on machine shop operators. In addition, much valuable time is expended by operators when having to change boring bar assemblies. Another problem exists with using progressively larger boring bar assemblies and that is that as the boring bar assembly increases in physical size the machine speed must be slowed down to accommodate the larger sizes thus slowing down production speed.
The present invention overcomes the above noted deficiencies in obtaining a wide range of boring bar assembly diameters by providing a lateral bar arrangement made integrally with the boring bar assembly structure disclosed in U.S. Pat. No. 2,838,316. This lateral bar improvement permits operating over a wide range of boring bar diameters while maintaining the compact structure of the assembly disclosed in said patent. Also by virtue of the improvement of this invention the range of diameters is achieved on a single assembly by simply repositioning the assembly along receptacles provided on the lateral bar. Thus, the improvement of the present invention permits the wide range of diameters to be achieved quickly on a simple structure forming part of a compact boring bar assembly without the need of completely replacing assemblies and without having to slow down production by having to reduce the speed of the machine.